This invention relates to an an ammunition cartridge assembly of a separate metal or plastic case head.
The use of plastic cases for explosive rounds has long been recognized as being desirable. U.S. Pat. Nos. 4,147,107--Ringdal and 3,842,739--Scanlon, et al show plastic cartridge cases. Joining the plastic case to a metal base has been a severe problem. A tight seal is necessary, and this is accomplished by stretching the plastic case over the metal base in an interference fit. This interference fit stresses the plastic. Eventually, splitting of the plastic occurs, particularly where the round has a long shelf life.
It is an object of the present invention to provide a unique ammunition cartridge having a plastic case with significantly reduced stress cracking and creep.
It is another object of the present invention to provide a unique multicomponent, plastic-cased ammunition cartridge possessing a high order of mechanical integrity of the component assembly and excellent waterproofness.